Wafer level integration for embedded cooling

ABSTRACT

Techniques for wafer level integration of embedded cooling structures for integrated circuit devices are provided. In one embodiment, a method includes forming channel structures on a first surface of a silicon first wafer, wherein the channel structures respectively comprise radial channels that extend from central fluid distribution areas, and wherein integrated circuits are formed on a second surface of the silicon first wafer that opposes the first surface. The method can further include bonding a manifold wafer to the first surface of the silicon wafer such that inlet openings formed through the manifold wafer respectively connect to the central fluid distribution areas, thereby enclosing the radial channels and forming a bonded structure.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with Government support under Contract No.:FA8650-14-C-7466 awarded by Defense Advanced Research Projects Agency(DARPA). The Government has certain rights in this invention.

BACKGROUND

The subject disclosure relates to wafer level integration for embeddedcooling.

SUMMARY

The following presents a summary to provide a basic understanding of oneor more embodiments of the invention. This summary is not intended toidentify key or critical elements, or delineate any scope of theparticular embodiments or any scope of the claims. Its sole purpose isto present concepts in a simplified form as a prelude to the moredetailed description that is presented later. In one or more embodimentsdescribed herein, devices and methods that facilitate wafer levelintegration of embedded cooling structures for integrated circuitdevices are described.

According to an embodiment, a method is provided. The method includesforming channel structures on a first surface of a silicon first wafer,wherein the channel structures respectively comprise radial channelsthat extend from central fluid distribution areas, and whereinintegrated circuits are formed on a second surface of the silicon firstwafer that opposes the first surface. The method can further includebonding a manifold wafer to the first surface of the silicon wafer suchthat inlet openings formed through the manifold wafer respectivelyconnect to the central fluid distribution areas, thereby enclosing theradial channels and forming a bonded structure.

According to another embodiment, another method is provided thatcomprises forming channel structures on a first surface of a manifoldfirst wafer, wherein the channel structures respectively comprise radialchannels that extend from central fluid distribution areas. The methodfurther comprises bonding the first surface of the manifold wafer to afirst surface of a silicon wafer, thereby enclosing the radial channelsand forming a bonded structure.

In another embodiment, a device is provided that comprises a siliconwafer, the silicon wafer comprising channel structures formed on a firstsurface of a silicon first wafer, wherein the channel structuresrespectively comprise radial channels that extend from central fluiddistribution areas. The silicon wafer further comprises integratedcircuits formed on a second surface of the silicon first wafer thatopposes the first surface. The device further comprises a manifold waferbonded to the first surface of the silicon wafer, wherein portions ofthe manifold wafer enclose the radial channels and wherein inletopenings formed through the manifold wafer respectively connect to thecentral fluid distribution areas.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic of an example, non-limiting device havingan integrated cooling architecture to implement two-phase cooling inaccordance with one or more embodiments described herein.

FIG. 2 illustrates a cross-sectional view of an example, non-limitingdevice having an integrated cooling architecture to implement two-phasecooling in accordance with one or more embodiments described herein.

FIG. 3 illustrates a top-down planar view of example channel structurein accordance with one or more embodiments described herein.

FIGS. 4A and 4B illustrate top-down planar views of an example siliconwafer in accordance with one or more embodiments described herein.

FIG. 5 illustrates a top-down planar view of an example manifold waferin accordance with one or more embodiments described herein.

FIGS. 6A-6D illustrate an example method for forming a bonded structurethat facilitates wafer level integration of embedded cooling inaccordance with one or more embodiments described herein.

FIGS. 7A-7C depict alternative views of a bonded structure thatfacilitates wafer level integration of embedded cooling in accordancewith one or more embodiments described herein.

FIGS. 8A-8D illustrate a method for forming individual chip structureswith embedded cooling in accordance with one or more embodimentsdescribed herein.

FIGS. 9A-9F illustrate another method for forming individual chips withembedded cooling in accordance with one or more embodiments describedherein.

FIGS. 10A-10C illustrate a method for assembly of a device having anintegrated cooling architecture to implement two-phase cooling inaccordance with one or more embodiments described herein.

FIG. 11 illustrates a schematic of another example, non-limiting devicehaving an integrated cooling architecture to implement two-phase coolingin accordance with one or more embodiments described herein.

FIGS. 12A and 12B illustrate top-down planar views of another examplemanifold wafer in accordance with one or more embodiments describedherein.

FIGS. 13A-13C illustrate another example method for wafer levelintegration of embedded cooling in accordance with one or moreembodiments described herein.

FIGS. 14A-14C depict alternative views of a bonded structure thatfacilitates wafer level integration of embedded cooling in accordancewith one or more embodiments described herein.

FIGS. 15A-15D illustrate another method for forming individual chipstructures with embedded cooling in accordance with one or moreembodiments described herein.

FIGS. 16A-16F illustrate another method for forming individual chipswith embedded cooling in accordance with one or more embodimentsdescribed herein.

FIGS. 17A-17C illustrate another method for assembly of a device havingan integrated cooling architecture to implement two-phase cooling inaccordance with one or more embodiments described herein.

FIG. 18 illustrates a flow diagram of an example, non-limiting methodfor wafer level integration of embedded cooling in accordance with oneor more embodiments described herein.

FIG. 19 illustrates a flow diagram of another example, non-limitingmethod for wafer level integration of embedded cooling in accordancewith one or more embodiments described herein.

FIG. 20 illustrates a flow diagram of another example, non-limitingmethod for wafer level integration of embedded cooling in accordancewith one or more embodiments described herein.

FIG. 21 illustrates a flow diagram of another example, non-limitingmethod for wafer level integration of embedded cooling in accordancewith one or more embodiments described herein.

FIG. 22 illustrates a flow diagram of another example, non-limitingmethod for wafer level integration of embedded cooling in accordancewith one or more embodiments described herein.

FIG. 23 illustrates a flow diagram of another example, non-limitingmethod for wafer level integration of embedded cooling in accordancewith one or more embodiments described herein.

DETAILED DESCRIPTION

The following detailed description is merely illustrative and is notintended to limit embodiments and/or application or uses of embodiments.Furthermore, there is no intention to be bound by any expressed orimplied information presented in the preceding Background or Summarysections, or in the Detailed Description section.

As conventional high performance integrated circuit chips are fabricatedsmaller and smaller, the reduced form factor can result in an increaseof power density within these smaller devices. As such, ahigh-performance integrated circuit chip can generate large amounts ofheat which can negatively affect the operation and performance of thedevice. Various solutions have been developed to aid heat extractionfrom a high-performance integrated circuit chip. With single-phasecooling, coolant is passed through the micro-channels and heated by theelectronic device. The heated coolant is then excreted from themicro-channels and passed to a liquid to liquid condenser/heat exchangerthat transfers the heat from the heated coolant. In two-phase cooling,instead of excreting heated liquid coolant, the liquid coolant is boiledfrom the micro-channels as it passes there through and vapor is excretedfrom the micro-channels to a condenser. Two-phase cooling systems canprovide greater cooling ability at a lower volume of coolant, lower massflow rate, and/or lower operating pressure than single-phase cooling.

One or more embodiments of the subject disclosure provide techniques forefficiently forming two-dimensional (2D) integrated circuit chips orchip stacks with embedded cooling structures, also referred to herein ascold plates, at the wafer level. In this regard, a plurality ofmicro-channel structures can be formed within a bonded structurecomprising a silicon wafer that is bonded to a manifold wafer. Thesilicon wafer can comprise a plurality of integrated circuits formed ona first surface thereof. In one embodiment, the micro-channel structurescan be patterned on a second surface of the silicon wafer. With thisembodiment, the manifold wafer can be bonded to the second surface ofthe silicon wafer so as to enclose the micro-channels. The manifoldwafer can further include a plurality of openings that respectivelyconnect to the micro-channel structures and provide for passing liquidcoolant into the micro-channels. In another embodiment, themicro-channel structures can be formed on a first surface of themanifold layer. With this embodiment, the first surface of the manifoldwafer can be bonded to the second surface of the silicon wafer so as toenclose the micro-channels. The manifold wafer can also include aplurality of openings that respectively connect to the micro-channelstructures and provide for passing liquid coolant into themicro-channels. In some implementations, in either of these embodiments,the silicon wafer and the manifold wafer can be thermally bonded tofacilitate heat transfer from the integrated circuit to themicro-channels.

The bonded structure can then be diced into individual integratedcircuit chip structures such that each of the integrated circuit chipsstructures includes at least one integrated circuit and a micro-channelstructure (or cold plate). In various implementations, the embeddedcooling structures can provide for two-phase cooling. With theseimplementations, the manner in which the bonded structure is diced canfacilitate exposing one or more openings in the micro-channels to allowliquid vapor to exist the micro-channels. In some implementations, theembedded cooling structures can also provide for single-phase cooling.In one or more embodiments, a chip package can be formed by mounting anindividual integrated circuit chip structure onto a substrate andforming a lid or cap over the integrated circuit chip structure so as toenclose the integrated circuit chip structure on the substrate. A first(inlet) opening can further be formed through the cap that connects toan opening in the manifold layer which further connects to themicro-channels of the cold plate to provide for passage of liquidcoolant into the micro-channels. A second (outlet) opening can be formedwithin the cap that allows for excretion of heated coolant or vapor fromthe micro-channels outside of the chip package.

One or more embodiments are now described with reference to thedrawings, wherein like referenced numerals are used to refer to likeelements throughout. In the following description, for purposes ofexplanation, numerous specific details are set forth in order to providea more thorough understanding of the one or more embodiments. It isevident, however, in various cases, that the one or more embodiments canbe practiced without these specific details.

With reference now to FIG. 1, an embodiment is shown wherein a chippackage 100 for two-phase cooling is illustrated with a corner of thechip package 100 cut away to render the inner structure visible. Thechip package 100 can comprise a substrate 102, a chip 104, a manifold106 (indicated by the dashed box), and a cap 108. A dielectric liquidcoolant can enter the cap 108 via an inlet opening 110, and traverse aninlet path 112 through the cap 108 to the manifold 106. The liquidcoolant can pass through the manifold 106 via an opening 114 and enterone or more cooling channels 116 on an upper surface of the chip 104.The one or more cooling channels 116 can radially extend away from thecenter of the chip 104. The liquid coolant can flow through the coolingchannels 116 towards the edges of the chip 104 and manifold 106. As thecoolant flows through the cooling channels 116, the coolant can absorbheat dissipating from the chip 104 and change phase from a liquid to avapor. Upon reaching the end of the cooling channels 116, the gaseouscoolant can escape into an outlet path 118 in the cap 108 and whichsurrounds the chip 104 and manifold 106. The gaseous coolant can flowthrough the outlet path 118 and exit the chip package 100 via an outletopening 120.

FIG. 2 illustrates a cross-sectional view of the chip package 100 with aportion of the chip package 100 magnified for more accurate referencing.Repetitive description of like elements employed in other embodimentsdescribed herein is omitted for sake of brevity.

The substrate 102 (e.g., an organic substrate) can comprise the base ofthe chip package 100. The chip 104 (e.g., a silicon chip), or a stack ofconjoined chips, can be electrically connected and bonded to thesubstrate 102 via an array of solder balls 202 (e.g., Lead (Pb)-freecontrolled collapse chip connections (C4s)). The chip 104 can beunderfilled with a cured underfill 204 to protect both the solderinterconnections and fragile back-end-of-line structure in an area ofconnection on the chip 104 from cyclic thermal mechanical fatiguefailure. The material properties of the cured underfill 204 can resultin a strong mechanical bond between the chip 104, with a low coefficientof thermal expansion (CTE) (about 2.9 parts per million (ppm)/degreesCelsius (C°)), and the substrate 102, with a much higher CTE (about 17ppm/C°). Further, a laminate 210 can coat an upper most surface of thesubstrate 102 that faces the cap 108.

In the embodiment shown, the cooling channels 116 can be etched into asurface of the chip 104 farthest from the substrate 102 (e.g., a topsurface of the chip 104). In other embodiments, the cooling channels 116may be etched into other (e.g., intermediary) surfaces of the chip 104.In some embodiments, the cooling channels 116 can be formed around acentral fluid distribution area that is aligned with the opening 114that extends through the manifold 106. Further, the cooling channels 116can extend radially from the central fluid distribution area toward theedges of the chip 104. Also, the width of the cooling channels 116 canincrease as the cooling channels 116 near one or more of the chip 104edges. Each channel (or in some embodiments, one or more channels) ofthe cooling channels 116 can have the same height as the other channelscomprising the cooling channels 116. The cooling channels 116 can guidethe coolant into a radial flow across the surface of the chip 104.

In some embodiments, the manifold 106 can be located on the chip 104 andform a lid over the cooling channels 116. The opening 114 in themanifold 106 can be aligned with the central fluid distribution area ofthe cooling channels 116. Further, the manifold 106 can cover the entiresurface of the chip 104 except for the opening 114 over a defined region(e.g., the center region) of the chip 104. Also, in some embodiments,the manifold 106 can stop short of extending entirely to the edges ofthe chip 104, thereby creating an opening enabling greater fluidcommunication between the cooling channels 116 and the outlet path 118.In other words, the manifold 106 can act as a lid covering the coolingchannels 116 and containing the dielectric coolant (in liquid or vaporphase) except over the central fluid distribution area and outmost edgesof the cooling channels 116.

In some embodiments, the manifold 106 can be a thin flexible materialhaving a CTE closely matched to the CTE of the chip 104. Materialchoices for the manifold 106 can include, but are not limited to, thinsilicon (<500 microns), thin glass (<200 microns) (e.g., WILLOW GLASS®)and the like. Thus, suitable materials for the manifold 106 can includematerials that are thin (typically less than 1 millimeter (mm)),flexible, and have similar CTE properties as the chip 104 material.Further, the manifold 106 can have a uniform thickness.

The manifold 106 can be bonded to the chip 104 by a bonding layer 206.The bonding layer 206 can bond the manifold 106 to the surface of thechip 104 into which the cooling channels 116 are etched (e.g., the topof the walls defining the cooling channels 116). The opening 114 canalso extend through the bonding layer 206. In one or more exemplaryembodiments, the bonding layer 206 comprises copper or another suitablemetal and is formed via soldering. In other embodiments, the bondinglayer 206 can comprise an anodic bond. Still in other embodiments, thebonding layer 206 can comprise an adhesive malleable enough to contourwith any (or, in some embodiments, one or more) curvatures of themanifold 106 and the chip 104. The bonding layer 206 can be a phenoxythermoplastic adhesive (e.g., a synthetic thermoplastic in the form ofpolyhydroxy ethers). For example, the adhesive can comprise a phenoxypolymer containing the chemical ingredient bisphenol-A-(epichlorohydrin)(e.g., PKHC, PKHB, PKHJ, PKHA, and PKHH), or the like in a solvent(e.g., N-Methyl-2-pyrrolidone (NMP), Methyl Ethyl Ketone (MEK),cyclohexanone, and glycol ethers). Also, the adhesive layer can be about2-5 microns thick (e.g., 3-4 microns). In various exemplary embodiments,the bonding layer 206 comprises a thermally conductive material. In thisregard, the thermally conductive bonding layer can improve thermalperformance by serving as an additional path for heat transfer from thechip 104 (and associated elements) to the cooling channels 116.

The cap 108 can interact with the manifold 106 and the laminatedsubstrate 102 via an interface 208. The interface 208 can be located inprimarily two positions. The first position 208 a of the interface 208can be between the cap 108 and the manifold 106. The second position 208b of the interface 208 can be between the cap 108 and the laminatedsubstrate 102. In some embodiments, the interface 208 can encircle theopening 114 on the manifold 106 at the first position 208 a and traversethe perimeter of the laminated substrate 102 at the second position 208b.

In some embodiments, the interface 208 can be a rigid high strength,room temperature curing structural adhesive with a modulus of elasticityof about 2 gigapascals (GPa) or more at both the first position 208 aand the second position 208 b. The interface 208 can comprise about28-32 milligrams (mg) of adhesive at the first position 208 a, whereinthe chip 104 can be about 21.2×26.6 mm in size, and about 500-600 mg ofadhesive at the second position 208 b, wherein the substrate 102 can beabout 50×50 mm and the cap can be about 48×48 mm in size. Also, it isunderstood that the mass dispense of the adhesive can be adjusted forvarious design dimensions. Further, in one embodiment, 45 micron spacerbeads can be used in the adhesive to achieve a 45 micron bond lineminimum at the first position 208 a.

In another embodiment, the interface 208 at the first position 208 a canbe a compliant, elastomeric adhesive with a modulus of about 2 to 15megapascals (MPa). The interface 208 at the second position 208 b can bea rigid high strength, room temperature curing structural adhesive witha modulus of elasticity of about 2 GPa or more. The interface 208 cancomprise about 28-32 mg of compliant adhesive at the first position 208a and about 500-600 mg of rigid adhesive at the second position 208 b.Spacer beads larger than 45 microns can be used to facilitate compliancein the structure with a corresponding increase in the mass of adhesivesdispensed at the first position 208 a and the second position 208 b.

In another embodiment, the interface 208 at the first position 208 a canbe a compliant, elastomeric pre-cast or pre-cut non-adhesive seal with amodulus of about 2 to 15 MPa, and can be used to provide compressiveloading during room temperature curing and provide a large temperaturerange of thermal mechanical stability of the chip package 100 structure.The interface 208 at the second position 208 b can be a rigid highstrength, room temperature curing structural adhesive with a modulus ofelasticity of about 2 GPa or more. The interface 208 can comprise about500-600 mg of rigid adhesive at the second position 208 b.

The cap 108 (e.g., a manifold typically comprising a brass alloy, acopper alloy, or an aluminum alloy but can comprise a polymer, ceramicor other material) can have at least one inlet opening 110 connected toleast one inlet path 112. The inlet path 112 can travel through the cap108 and align with the opening 114 in the manifold 106. As such, apathway can be created in which dielectric coolant can pass through thecap 108 and the manifold 106 to the central fluid distribution area andinto the cooling channels 116. Further, the cap 108 can have at leastone outlet path 118 surrounding the chip 104, bonding layer 206,manifold 106, and first position 208 a of the interface 208. The atleast one outlet path 118 can connect to at least one outlet opening120. As such, a pathway can be created in which heated dielectriccoolant (e.g., liquid and/or vapor) can escape the cooling channels 116and exit the chip package 100.

FIG. 3 illustrates a top-down planar view of an example cooling channelstructure 300 in accordance with one or more embodiments describedherein. Repetitive description of like elements employed in otherembodiments described herein is omitted for sake of brevity.

The cooling channel structure 300 includes a plurality of coolingchannels 116 (represented by the open white spaces) defined by walls 302(represented by the thick black lines). The cooling channels 116radially extend from a central fluid distribution area 304. The centralfluid distribution area 304 can connect with the opening 114 in themanifold 106 (and in some embodiments, aligned openings in the bondinglayer 206 and/or the interface 208) which connects to the inlet path112. Liquid coolant can enter the central fluid distribution area 304via the opening 114 and be radially dispersed via one more openings 306in the central fluid distribution area 304 (as indicated by the squigglyarrow lines). In the embodiment shown, the cooling channels 116 canbranch into smaller sub-channels as they extend radially from thecentral fluid distribution area 304. For example, channel 116 a, canbranch into sub-channels 116 b, which can branch into sub-channels 116 cbased on formation of the walls 302 at various increasing radii (e.g.,r, 2r, 4r, etc.) from the central fluid distribution area 304. Eachchannel (or in some embodiments, one or more channels) of the coolingchannels 116 can have the same depth (or height) as the other channelscomprising the cooling channels 116.

FIGS. 4A and 4B illustrates top-down planar views of an example siliconwafer 400 comprising a plurality of cooling channel structures (e.g., aplurality of cooling channel structures 300) formed on a surface of thesilicon wafer 400 in accordance with one or more embodiments describedherein. FIG. 4A illustrates a top-down planar view of the first surface401 (e.g., the topside) of the silicon wafer 400 and FIG. 4B illustratesa top-down planar view of the second surface 402 (e.g., the backside) ofthe silicon wafer 400. Repetitive description of like elements employedin other embodiments described herein is omitted for sake of brevity.

In one embodiment, in order to efficiently (e.g., in terms of time andcost) fabricate a plurality of chip packages with embedded cooling(e.g., such as chip package 100 or similar chip packages), a pluralityof cooling channel structures 300 can be formed on one surface (e.g.,the first surface 401) of a silicon wafer 400 using a suitable etchingtechnique (e.g., deep reactive ion etching (RIE), a wet etchant, or thelike). The cooling channels 116 of the respective cooling channelstructures 300 on the first surface 401 of the silicon wafer 400 areexposed. The particular number and arrangement of the respective coolingchannel structures 300 can vary. According to this embodiment, the otherside of the silicon wafer (e.g., the second surface 402) can include aplurality of integrated circuits 404 formed thereon that respectivelyoppose the cooling channel structures 300. For example, one or more ofthe integrated circuits 404 can include an application-specificintegrated circuit (ASIC), a staggered pin grid array (SPGA), or anothersuitable integrated circuit. The depth of the cooling channels 116 ofthe respective cooling channel structures 300 can vary such that theyextend partially through the thickness of the silicon wafer 400 and donot puncture the integrated circuits formed on the backside of thesilicon wafer 400. In some implementations, the integrated circuits 404can be formed on the second surface 402 of the silicon wafer prior toformation of the cooling channel structures 300 on the first surface 401of the silicon wafer 400. In other implementations, the integratedcircuits 404 can be formed on the second surface 402 of the siliconwafer after the formation of the cooling channel structures 300 on thefirst surface 401 of the silicon wafer 400.

FIG. 5 illustrates a top-down planar view of an example manifold wafer500 in accordance with one or more embodiments described herein. Thematerial of the manifold wafer 500 can be or include one or more of thematerials of the manifold 106 discussed supra. Repetitive description oflike elements employed in other embodiments described herein is omittedfor sake of brevity.

In accordance with the subject embodiment, the manifold wafer 500 caninclude a plurality of openings 114 can extend throughout the entirethickness of the manifold wafer 500 such that liquid coolant can passthrough the respective openings from one side of the manifold wafer tothe other. According with this embodiment, the first surface 501 and thesecond opposing surface (not show) of the manifold wafer 500 can be thesame or substantially the same. The openings 114 can be arranged suchthat their positions correspond to the respective positions of thecentral fluid distribution areas (e.g., central fluid distribution area304) of the respective cooling channel structures on the silicon wafer400. Thus when the manifold wafer 500 is subsequently bonded to thefirst surface 401 of the silicon wafer 400, the respective openings 114can be aligned with and connect to the respective central fluiddistribution areas 304.

FIGS. 6A-6D illustrate a method for wafer level integration of embeddedcooling in accordance with one or more embodiments described herein.Repetitive description of like elements employed in other embodimentsdescribed herein is omitted for sake of brevity.

With reference to FIGS. 6A and 6B, according to the embodiment shown, abonding layer 206 can be formed on the first surface 501 of the manifoldwafer 500 such that the bonding layer 206 exposes at least the openings114 of the manifold layer. In implementations in which the manifoldwafer 500 comprises silicon, the bonding layer 206 can comprise a copperbond, a solder bond, or an adhesive bond. In other implementations inwhich the manifold wafer comprises glass, the bonding layer 206 cancomprise a copper bond, a solder bond, or an adhesive bond. In variousexemplary implementations, the bonding layer 206 comprises a thermallyconductive material. Other suitable materials for the bonding layer 206are discussed supra with reference to FIG. 2. Although the bonding layer206 is shown substantially covering the first surface 501 (aside fromopenings 114) of the manifold wafer 500, it should be appreciated thatthe amount of coverage of the bonding layer 206 on first surface 501 ofthe manifold wafer 500 can cover less than the entire surface based onthe type of bonding material/method used.

As shown in FIG. 6C, the first surface 401 of the silicon wafer 400 canfurther be bonded to the manifold wafer 500 via the bonding layer 206formed on the first surface 501 of the manifold wafer 500 so as toenclose the cooling channels 116 exposed on the first surface 401 of thesilicon wafer 400. In addition, the openings 114 in the manifold wafer500 can be aligned with the respective central fluid distribution areas304 of the cooling channel structures 300 formed on the first surface401 of the silicon wafer 400. The resulting bonded structure 600 isshown in FIG. 6D. In another embodiment, (not shown), the bonding layer206 can be formed on the first surface 401 of the silicon wafer 400. Forexample, the bonding layer 206 can be formed on the top surfaces of thewalls 302 of cooling channel structures 300. The first surface 401 canfurther be bonded to the first surface 501 or the second surface 502 ofthe manifold wafer 500 via the bonding layer 206 formed on the topsurfaces of the walls 302 of the cooling channels 116.

FIGS. 7A-7C depict alternative views of bonded structure 600. Forexample, FIG. 7A depicts a view of the bonded structure 600 shown inFIG. 6D flipped over. FIG. 7B depicts a 2D cross-sectional view of aportion of bonded structure 600 taken along the x-axis between points y1and y2 shown relative to the bonded structure 600 in FIG. 7A. FIG. 7Cdepicts a 2D top-down planar view of a portion of bonded structure 600taken along the z-axis between points y1 and y2 shown relative to thebonded structure 600 in FIG. 7A.

As shown in FIGS. 6D and 7A-7C, the bonded structure 600 comprises themanifold wafer 500 bonded to the first surface 401 of the silicon wafer400 comprising the cooling channel structures 300. Thus the manifoldwafer 500 provides a cap or cover so as to enclose the cooling channels116 of the cooling channel structures 600 provided on the first surface401 of the silicon wafer 400. The respective openings 114, which arealigned with the central fluid distribution areas 304 of the coolingchannel structures 300, provide an inlet for liquid coolant into thecooling channels 116. The exposed second surface 502 of the manifoldwafer 500 further includes the openings 114. The openings 114 extendthrough the manifold wafer 500 and the bonding layer 206. The secondsurface 402 of the silicon wafer 400 comprises the integrated circuits404 formed thereon. The manifold wafer 500 is bonded to the siliconwafer 400 via the bonding layer 206. In embodiments in which the bondinglayer 206 comprises a thermally conductive material, the bonding layer206 facilitates enhance thermal conductance from heat generated by theintegrated circuits 404 to the cooling channels 116.

FIGS. 8A-8D illustrate a method for forming individual chip structureswith embedded cooling in accordance with one or more embodimentsdescribed herein. Repetitive description of like elements employed inother embodiments described herein is omitted for sake of brevity.

With reference to FIGS. 8A and 8B in one or more embodiments, aplurality of individual chip structures with embedded cooling can beformed using a dual dicing technique, wherein bonded structure 600 isdiced in two phases. In accordance with the embodiment shown in FIGS. 8Aand 8B, in the first phase, portions of the manifold wafer 500 andbonding layer 206 can be removed (i.e., via dicing, cutting, etched,etc.) so as to expose openings 802 in the cooling channels 116. FIG. 8Aillustrates a cross-sectional view of a resulting intermediate structure800 formed via the first dicing phase and FIG. 8B illustrates a top downview of the intermediate structure 800. In one or more embodiments,because the openings 802 open on a first surface 401 (e.g., as opposedto a side surface) of the silicon wafer 400, the openings 802 areconfigured to direct heated liquid coolant or vapor to flow in avertical direction out of the cooling channels 116. For example, theopenings 802 can be configured to direct liquid or vapor out of theradial channels in a direction about 90° relative to the first surfaceof the silicon wafer. In some embodiments, the openings 114 in themanifold wafer 500 can be formed at this first phase as well (e.g., inassociating with forming the openings 802). According to theseembodiments, the manifold wafer 500 of bonded structure 600 would nothave openings 114.

In the second dicing phase, the intermediate structure 800 can beseparated into individual chip structures 804 by dicing (e.g., cutting,splitting, etc.) the silicon wafer 400 along the dashed arrowed lines.FIGS. 8C and 8D illustrate such individual chip structures 804 resultingfrom the second dicing phase. FIG. 8C illustrates a cross-sectional viewand FIG. 8D illustrates a top-down planar view of chip structures 804.As shown in FIGS. 8C and 8D, each of the chip structures 804 include achip 104 having cooling channels 116 provided on a first surface and atleast one integrated circuit 404 provided on the opposing, secondsurface. The chip structures 804 further include a manifold 106 bondedto a portion of the first surface of chip via bonding layer 206. Themanifold 106 thus encloses a portion of the cooling channels 116.Openings 802 in the cooling channels are established around theperimeter of manifold 106.

FIGS. 9A-9F illustrate another method for forming individual chipstructures with embedded cooling in accordance with one or moreembodiments described herein. Repetitive description of like elementsemployed in other embodiments described herein is omitted for sake ofbrevity.

With reference to FIGS. 9A and 9B in another embodiment, a plurality ofindividual chip structures 804 with embedded cooling can be formed usinga dual dicing technique wherein bonded structure 600 is diced in againtwo phases. However, in accordance with this other embodiment as shownin FIGS. 9A and 9B, in the first phase, portions of the entire bondedstructure 600 can be diced (e.g., cut, split, etc.) along dashed arrowlines to generate intermediate structures 900 shown in FIGS. 9C and 9D.The intermediate structures 900 can further be diced (e.g., via etching,dicing, cutting, etc.) in a second phase along the dashed arrow linesshown on intermediate structures 900 so as to expose openings 802 in thecooling channels 116. The resulting chip structures 804 are shown inFIGS. 9E and 9F. In one or more embodiments, because the openings 802open on a top surface (e.g., as opposed to a side surface) of themanifold 106, the openings 802 are configured to direct heated liquidcoolant or vapor to flow in a vertical direction out of the coolingchannels 116. In some embodiments, the openings 114 in the manifoldwafer 500 can be formed at this first phase as well. According to theseembodiments, the manifold wafer 500 of bonded structure 600 and theintermediate structures 900 would not have openings 114.

FIGS. 10A-10C illustrate a method for assembly of a chip package (e.g.,chip package 100) having an integrated cooling architecture to implementtwo-phase cooling in accordance with one or more embodiments describedherein. Repetitive description of like elements employed in otherembodiments described herein is omitted for sake of brevity.

As shown in FIG. 10A, the chip structure 804 can be mounted onto asubstrate 102 (e.g., via the side of the chip comprising the at leastone integrated circuit 404) by underfilling the chip 104 with curedunderfill 204 in conjunction with solder balls 202 (e.g., Pb free C4s).In some implementations the chip structure 804 and the substrate 102 canalso be prepared for attaching the cap 108. For example, oxygen plasmatreatment of the chip structure and the substrate 102 before applicationof the interface 208 can help to clean and to enhance coating, wetting,and adhesion. Further, the cap 108 can be cleaned using, for example,ultrasonic cleaning techniques. Further, in some embodiments, theportions of the substrate around the mounted chip structure 804 can belaminated with a laminate 210 coat.

As shown in 10B, the cap 108 can then be applied so as to enclose thechip structure on the substrate 102 via interfaces 208. For example, theinterface 208 can be applied to first position 208 a on the manifold 106and to a second position 208 b on the substrate 102. Wherein theinterface 208 can be an adhesive at the first position 208 a, theadhesive can be applied in a pattern to achieve maximum coverage whileavoiding any overflow into the cooling channels 116 or central fluiddistribution area. Wherein the interface 208 can be a pre-cast orpre-cut seal, the seal can be positioned so as to surround the opening114 in the manifold 106. As described above in regards to the structureof the chip package 100, the interface 208, at the first position 208 a,can be any one of a rigid adhesive, a compliant adhesive, or a pre-castor pre-cut non-adhesive seal. As shown in FIG. 10C, the chip package 100can be finalized by establishing the at least one inlet opening 110, theoutlet opening 120, the inlet path 112 and the outlet path 118.

FIG. 11 illustrates a cross-sectional view of another example chippackage 1100 in accordance with one or more embodiments disclosedherein. Repetitive description of like elements employed in otherembodiments described herein is omitted for sake of brevity.

Chip package 1100 includes same or similar elements as chip package 100with the exception of the chip structure including the embedded cooling.In particular, as shown in the enlarged view of circled area, the chipstructure with the embedded cooling comprises a chip 1102 bonded to amanifold 1104 via a bonding layer 206. Similar to chip 104, chip 1102can include at least one integrated circuit (not shown) formed on asurface thereof. In some implementations, the integrated circuit can beformed on the bottom surface of the chip 1102 contacting the substrate102 via the solder balls 202 and cured underfill 204. In otherimplementations, the integrated circuit can be formed on the top surfaceof the chip 1102 contacting the bonding layer 206. Still in otherimplementations, the integrated circuit can be formed within the middleof the chip 1102.

Unlike chip 104, the chip 1102 does not include the cooling channels116. On the contrary, the cooling channels 116 are formed in themanifold 1104. The manifold 1104 can include same or similar materialsas the manifold 106. In the embodiment shown, the cooling channels 116can extend partially through the manifold 1104 from the lower surface ofthe manifold 1104 such that they do not puncture through the opposingtop surface of the manifold 1104. For example, the depth of the coolingchannels 116 can vary within the thickness of the manifold 1104 suchthat at a portion 1106 of the manifold 1104 encloses the coolingchannels 116. Similar to chip package 100, the opening 114 can furtherpass through the interface 208 and the cap 108 and connect to the inletchannel 112. An opening 114 can be formed through at least a portion ofthe manifold 1104 that connects to the cooling channels 116. In someembodiments, the cooling channels 116 can extend entirely through thethickness of the manifold 1104. In accordance with chip package 1100,the bonding layer 206 can be made with a thermally conductive materialto facilitate conducting heat from the integrated circuit on the chip1102 (and other electrical components) to the cooling channels 1116.

FIGS. 12A and 12B illustrate top-down planar views of another examplemanifold wafer 1200 in accordance with one or more embodiments describedherein. FIG. 12A illustrates a first surface 1201 of the manifold waferand FIG. 12B illustrates a second surface 1202 of the manifold wafer1200. The first surface 1201 opposes the second surface 1202. As shownin FIG. 12A, similar to the first surface 401 of silicon wafer 400, thefirst surface 1201 of the manifold wafer 1200 can comprises a pluralityof cooling channel structures 300 formed thereon. The cooling channels116 of the cooling channel structures can be exposed. Similar to thefirst surface 501 of the manifold wafer 500, the second surface 1202 ofthe manifold wafer 1200 can include a plurality of openings 114. Theplurality of openings 114 can respectively extend through a portion ofthe manifold wafer 1200 and respectively connect to the central fluiddistribution areas 304 of cooling channel structures 300 formed on theopposing, first surface 1201 of the manifold wafer. Repetitivedescription of like elements employed in embodiments described herein isomitted for sake of brevity.

In some embodiments, the manifold wafer 1200 can be formed by etchingthe cooling channel structures 300 on the first surface 1201 of themanifold wafer 1200 (e.g., using a suitable etching technique such asRIE, a wet etchant, or the like). The openings 114 can further be formed(e.g., using a suitable etching technique such as RIE, a wet etchant, orthe like) through the second surface 1202 of the manifold wafer 1200such that the openings 114 respectively align with and connect to thecentral fluid distribution areas 304. In other embodiments, the manifoldwafer 1200 can be formed by etching the openings 114 in the secondsurface 1202 of the manifold wafer 1200 partially or entirely throughthe thickness of the manifold wafer 1200. The cooling channel structures300 can further be etched on the first surface 1201 of the manifold suchthat the central fluid distribution areas 304 respectively align withand connect to the openings.

FIGS. 13A-13C illustrate a method for wafer level integration ofembedded cooling in accordance with one or more embodiments describedherein. Repetitive description of like elements employed in otherembodiments described herein is omitted for sake of brevity.

With reference to FIGS. 13A and 13B, according to the embodiment shown,a bonding layer 206 can be formed on the first surface 1201 of themanifold wafer 1200 comprising the exposed cooling channels 116. Inimplementations in which the manifold wafer 1200 comprises silicon, thebonding layer 206 can comprise a copper bond, a solder bond, or anadhesive bond. In other implementations in which the manifold wafer 1200comprises glass, the bonding layer 206 can comprise a copper bond, asolder bond, or an adhesive bond. In various exemplary implementations,the bonding layer 206 comprises a thermally conductive material. Othersuitable materials for the bonding layer 206 are discussed supra withreference to FIG. 2. Although the bonding layer 206 is shownsubstantially covering the first surface 1201 of the manifold wafer 500,it should be appreciated that the amount of coverage of the bondinglayer 206 on first surface 1201 of the manifold wafer 1200 can coverless than the entire surface based on the type of bondingmaterial/method used. For example, in some implementations, the bondinglayer 206 can be formed on the surfaces of the walls 302 of therespective cooling channel structures 300.

As shown in FIG. 13C, the first surface a silicon wafer 1302 can bebonded to the manifold wafer 1200 via the bonding layer 206, therebygenerating bonded structure 1300. Similar to the second surface 402 ofsilicon wafer 400, at least one surface (or intermediary layer) of thesilicon wafer 1302 can comprise a plurality of integrated circuits 404formed thereon (not shown). The integrated circuits can respectivelyalign with the respective cooling channel structures 300 formed on thefirst surface 1201 of the manifold wafer 1200. In some implementations,the integrated circuits can be formed on the bottom surface of thesilicon wafer 1302 opposite the top surface of the silicon wafer 1302bonded to the manifold wafer 1200 (via the bonding layer 206). In otherembodiments, the integrated circuits can be formed on the top surface ofthe silicon wafer that opposes the bottom surface of the silicon wafer1302. By bonding the first surface 1201 of the manifold wafer 1200 tothe silicon wafer 1302, the exposed cooling channels 116 are enclosed.

In other implementations, (not shown), the bonding layer 206 can beformed on the top surface of the silicon wafer 1302. The first surface1201 of the manifold wafer 1200 can further be bonded to the siliconwafer 1302 by pressing the first surface 1201 of the manifold wafer 1200onto the top surface of the silicon wafer 1302 comprising the bondinglayer 206 formed thereon, thereby resulting in the bonded structure1300.

FIGS. 14A-14C depict alternative views of bonded structure 1300. Forexample, FIGS. 13A and 13B depict a 2D cross-sectional view of a portionof bonded structure 600 taken along the x-axis between points y1 and y2shown relative to the bonded structure 1300 in FIG. 13C. FIG. 13Aillustrates an embodiment wherein the integrated circuits 404 are formedon a bottom surface of the silicon wafer 1302, and FIG. 13B illustratesan embodiment wherein the integrated circuits 404 are formed on a topsurface of the silicon wafer 1302. FIG. 13C depicts a 2D top-down planarview of a portion of bonded structure 1300 taken along the z-axisbetween points y1 and y2 shown relative to the bonded structure 1300 inFIG. 13C.

As shown in FIGS. 13C and 14A-14C, the bonded structure 1300 comprisesthe manifold wafer 1200 bonded to the silicon wafer 1302 such that thefirst surface 1201 of the manifold wafer 1200 comprising the exposedcooling channels 116 contacts a top surface of the silicon wafer 1302(e.g., via the bonding layer 206). Thus the silicon wafer 1302 providesa cap or cover so as to enclose the cooling channels 116. Further, therespective openings 114, which are aligned with the central fluiddistribution areas 304 of the cooling channel structures 300, provide aninlet for liquid coolant into the cooling channels 116. In embodimentsin which the bonding layer comprises a thermally conductive material,the bonding layer 206 facilitates enhance thermal conductance from heatgenerated by the integrated circuits 404 to the cooling channels 116.

FIGS. 15A-15D illustrate a method for forming individual chip structureswith embedded cooling in accordance with one or more embodimentsdescribed herein. Repetitive description of like elements employed inother embodiments described herein is omitted for sake of brevity.

With reference to FIGS. 15A and 15B in one or more embodiments, aplurality of individual chip structures with embedded cooling can beformed using a dual dicing technique, wherein bonded structure 1300 isdiced in two phases. In accordance with the embodiment shown in FIGS.15A and 15B, in the first phase, portions of the manifold wafer 1200 canbe removed (i.e., via etching, dicing, cutting, etc.) so as to exposeopenings 1502 in the cooling channels 116. FIG. 15A illustrates across-sectional view of a resulting intermediate structure 1500 formedvia the first dicing phase and FIG. 15B illustrates a top down view ofthe intermediate structure 1500. In one or more embodiments, because theopenings 1502 open on a first surface 1201 (e.g., as opposed to a sidesurface) of the manifold wafer 1200, the openings 1502 are configured todirect heated liquid coolant or vapor to flow in a vertical directionout of the cooling channels 116. In some embodiments, the openings 114in the manifold wafer 1200 can be formed at this first phase as well(e.g., in association with formation of the openings 1502). According tothese embodiments, the manifold wafer 1200 of bonded structure 1300would not have openings 114.

In the second dicing phase, the intermediate structure 1500 can beseparated into individual chip structures 1504 by dicing (e.g., cutting,splitting, etc.) the manifold wafer 1200, the bonding layer 206 and thesilicon wafer 1302 along the dashed arrowed lines shown in FIGS. 15A and15B. FIGS. 15C and 15D illustrate such individual chip structures 1504resulting from the second dicing phase. FIG. 15C illustrates across-sectional view and FIG. 15D illustrates a top-down planar view ofchip structures 1504. As shown in FIGS. 15C and 15D, each of the chipstructures 1504 include a chip 104 having cooling channels 116 providedwithin a manifold 1104 with an opening 114 that connects to the coolingchannels (e.g., via the central fluid distribution area 304). The chipstructures 1504 further include a chip 1102 bonded to the surface of themanifold 1104 comprising the cooling channels 116. Openings 1502 in thecooling channels 116 are established around the perimeter of manifold1104.

FIGS. 16A-16F illustrate another method for forming individual chipstructures with embedded cooling in accordance with one or moreembodiments described herein. Repetitive description of like elementsemployed in other embodiments described herein is omitted for sake ofbrevity.

With reference to FIGS. 16A and 16B in another embodiment, a pluralityof individual chip structures 1504 with embedded cooling can be formedusing a dual dicing technique wherein bonded structure 1300 is diced inagain two phases. However, in accordance with this other embodiment asshown in FIGS. 16A and 16B, in the first phase, portions of the entirebonded structure 1300 can be diced (e.g., cut, split, etc.) along thedashed arrow lines shown in FIGS. 16A and 16B to generate intermediatestructures 1600 shown in FIGS. 16C and 16D. The intermediate structures1600 can further be diced (e.g., via etching, dicing, cutting, etc.) ina second phase along the dashed arrow lines shown on intermediatestructures 1600 of FIGS. 16C and 16D so as to expose openings 1502 inthe cooling channels 116. The resulting chip structures 1504 are shownin FIGS. 16E and 16F. In one or more embodiments, because the openings1502 open on a top surface (e.g., as opposed to a side surface) of themanifold 1104, the openings 1502 are configured to direct heated liquidcoolant or vapor to flow in a vertical direction out of the coolingchannels 116. In some embodiments, the openings 114 in the manifoldwafer 1200 can be formed at this first phase as well. According to theseembodiments, the manifold wafer 1200 of bonded structure 1300 and theintermediate structures 1600 would not have openings 114.

FIGS. 17A-17C illustrate a method for assembly of a chip package (e.g.,chip package 1100) having an integrated cooling architecture toimplement two-phase cooling in accordance with one or more embodimentsdescribed herein. Repetitive description of like elements employed inother embodiments described herein is omitted for sake of brevity.

As shown in FIG. 17A, the chip structure 1504 can be mounted onto asubstrate 102 (e.g., via the chip 1102) by underfilling the chip 1102with cured underfill 204 in conjunction with solder balls 202 (e.g., Pbfree C4s). In some implementations the chip structure 1504 and thesubstrate 102 can also be prepared for attaching the cap 108. Forexample, oxygen plasma treatment of the chip structure and the substrate102 before application of the interface 208 can help to clean and toenhance coating, wetting, and adhesion. Further, the cap 108 can becleaned using, for example, ultrasonic cleaning techniques. Further, insome embodiments, the portions of the substrate around the mounted chipstructure 1504 can be laminated with a laminate 210 coat.

As shown in 17B, the cap 108 can then be applied so as to enclose thechip structure 1504 on the substrate 102 via interfaces 208. Forexample, the interface 208 can be applied to first position 208 a on themanifold 1104 and to a second position 208 b on the substrate 102.Wherein the interface 208 can be an adhesive at the first position 208a, the adhesive can be applied in a pattern to achieve maximum coveragewhile avoiding any overflow into the cooling channels 116 or centralfluid distribution area. Wherein the interface 208 can be a pre-cast orpre-cut seal, the seal can be positioned so as to surround the opening114 in the manifold 1104. As described above in regards to the structureof the chip package 1100, the interface 208, at the first position 208a, can be any one of a rigid adhesive, a compliant adhesive, or apre-cast or pre-cut non-adhesive seal. As shown in FIG. 17C, the chippackage 1100 can be finalized by establishing the at least one inletopening 110, the outlet opening 120, the inlet path 112 and the outletpath 118.

FIGS. 18-23 illustrate various methodologies in accordance with thedisclosed subject matter. While, for purposes of simplicity ofexplanation, the methodologies are shown and described as a series ofacts, it is to be understood and appreciated that the disclosed subjectmatter is not limited by the order of acts, as some acts can occur indifferent orders and/or concurrently with other acts from that shown anddescribed herein. For example, those skilled in the art will understandand appreciate that a methodology could alternatively be represented asa series of interrelated states or events, such as in a state diagram.Moreover, not all illustrated acts can be required to implement amethodology in accordance with the disclosed subject matter.

FIG. 18 illustrates a flow diagram of an example, non-limiting methodfor wafer level integration of embedded cooling in accordance with oneor more embodiments described herein. Repetitive description of likeelements employed in other embodiments described herein is omitted forsake of brevity.

At 1802, channel structures (e.g., cooling channel structures 300) areformed on a first surface (e.g., first surface 401) of a silicon firstwafer (silicon wafer 400), wherein the channel structures respectivelycomprise radial channels (e.g., cooling channels 116) that extend fromcentral fluid distribution areas (e.g., central fluid distribution areas304), and wherein integrated circuits (e.g., integrated circuits 404)are formed on a second surface (e.g., second surface 402) of the siliconfirst wafer that opposes the first surface. At 1804, a manifold wafer(e.g., manifold wafer 500) is bonded to the first surface of the siliconwafer such that inlet openings (e.g., openings 114) formed through themanifold wafer respectively connect to the central fluid distributionareas, thereby enclosing the radial channels and forming a bondedstructure (e.g., bonded structure 600).

FIG. 19 illustrates a flow diagram of another example, non-limitingmethod for wafer level integration of embedded cooling in accordancewith one or more embodiments described herein. Repetitive description oflike elements employed in other embodiments described herein is omittedfor sake of brevity.

At 1902, channel structures (e.g., cooling channel structures 300) areformed on a first surface (e.g., first surface 401) of a silicon firstwafer (silicon wafer 400), wherein the channel structures respectivelycomprise radial channels (e.g., cooling channels 116) that extend fromcentral fluid distribution areas (e.g., central fluid distribution areas304), and wherein integrated circuits (e.g., integrated circuits 404)are formed on a second surface (e.g., second surface 402) of the siliconfirst wafer that opposes the first surface. At 1904, a manifold wafer(e.g., manifold wafer 500) is bonded to the first surface of the siliconwafer such that inlet openings (e.g., openings 114) formed through themanifold wafer respectively connect to the central fluid distributionareas, thereby enclosing the radial channels and forming a bondedstructure (e.g., bonded structure 600). At 1906, portions of themanifold wafer respectively enclosing outward portions of the radialchannels are removed, thereby forming outlet openings (e.g., openings802) for the radial channels. At 1908, the bonded structure (e.g.,intermediate structure 800) is diced between the channel structures(e.g., along the dashed lines shown on intermediate structure 800 inFIGS. 8A and 8B), thereby forming a plurality of chip structures withembedded cooling (e.g., chip structures 804).

FIG. 20 illustrates a flow diagram of another example, non-limitingmethod for wafer level integration of embedded cooling in accordancewith one or more embodiments described herein. Repetitive description oflike elements employed in other embodiments described herein is omittedfor sake of brevity.

At 2002, a chip structure is mounted to a substrate (e.g., chipstructure 804). The chip structure comprise a chip (e.g., chip 104),that includes least one integrated circuit (e.g., integrated circuit404), and a channel structure (e.g., cooling channel structure 300),wherein the channel structure is formed on a first surface of the chip.The channel structure comprises radial channels (e.g., cooling channels116) that extend from a central fluid distribution area (e.g., centralfluid distribution area 304), and comprise outlet openings (e.g.,openings 802), and a manifold (e.g., manifold 106) formed on a portionof the chip enclosing portions of the radial channels excluding theoutlet openings. The manifold also comprises an inlet opening (e.g.,opening 114) that connect to the central fluid distribution area. At2004, a cap (e.g., cap 108) is attached to the chip structure and thesubstrate, thereby enclosing the chip structure on the substrate andforming outlet paths (e.g., outlet paths 118) between the outletopenings and the cap. At 2006, forming an inlet path (e.g., inlet path112) is formed through the cap that connects to the inlet opening, andat 2008, one or more second outlet openings (e.g., outlet opening 120)are formed in the cap that connect to the outlet paths.

FIG. 21 illustrates a flow diagram of another example, non-limitingmethod for wafer level integration of embedded cooling in accordancewith one or more embodiments described herein. Repetitive description oflike elements employed in other embodiments described herein is omittedfor sake of brevity.

At 2102, channel structures (e.g., cooling channel structures 300) areformed on a first surface (e.g., first surface 1201) of a manifold firstwafer (e.g., manifold wafer 1200), wherein the channel structuresrespectively comprise radial channels (e.g., cooling channels 116) thatextend from central fluid distribution areas (e.g., central fluiddistribution areas 304). At 1204, and the first surface of the manifoldwafer is bonded to a first surface of a silicon wafer (e.g., siliconwafer 1302), thereby enclosing the radial channels and forming a bondedstructure (e.g., bonded structure 1300).

FIG. 22 illustrates a flow diagram of another example, non-limitingmethod for wafer level integration of embedded cooling in accordancewith one or more embodiments described herein. Repetitive description oflike elements employed in other embodiments described herein is omittedfor sake of brevity.

At 2202, channel structures (e.g., cooling channel structures 300) areformed on a first surface (e.g., first surface 1201) of a manifold firstwafer (e.g., manifold wafer 1200), wherein the channel structuresrespectively comprise radial channels (e.g., cooling channels 116) thatextend from central fluid distribution areas (e.g., central fluiddistribution areas 304). At 2204, and the first surface of the manifoldwafer is bonded to a first surface of a silicon wafer (e.g., siliconwafer 1302), thereby enclosing the radial channels and forming a bondedstructure (e.g., bonded structure 1300). At 2206, inlet openings (e.g.,openings 114) are formed through a second surface (e.g., second surface1202) of the manifold wafer, wherein the inlet openings respectivelyconnect to the central fluid distribution areas. At 2208, portions ofthe manifold wafer respectively enclosing outward portions of the radialchannels are removed, thereby forming outlet openings (e.g., openings1502) for the radial channels. At 2210, the bonded structure (e.g.,intermediate structure 1500) is diced between the channel structures(e.g., along the dashed lines indicated in FIGS. 15A and 15B), therebyforming a plurality of chip structures with embedded cooling (e.g., chipstructures 1504).

FIG. 23 illustrates a flow diagram of another example, non-limitingmethod for wafer level integration of embedded cooling in accordancewith one or more embodiments described herein. Repetitive description oflike elements employed in other embodiments described herein is omittedfor sake of brevity.

At 2302, a chip structure is mounted to a substrate (e.g., chipstructure 1504). The chip structure comprise a chip (e.g., chip 1102),that includes least one integrated circuit (e.g., integrated circuit404), and a manifold (e.g., manifold 1104) bonded to the chip. Themanifold comprises a channel structure (e.g., cooling channel structure300), that comprises channel comprises radial channels (e.g., coolingchannels 116) that extend from a central fluid distribution area (e.g.,central fluid distribution area 304), an inlet opening (e.g., opening114) that connects to the central fluid distribution area, and outletopenings (e.g., openings 1502), for the radial channels. At 2304, a cap(e.g., cap 108) is attached to the chip structure and the substrate,thereby enclosing the chip structure on the substrate and forming outletpaths (e.g., outlet paths 118) between the outlet openings and the cap.At 2306, forming an inlet path (e.g., inlet path 112) is formed throughthe cap that connects to the inlet opening, and at 2008, one or moresecond outlet openings (e.g., outlet opening 120) are formed in the capthat connect to the outlet paths.

The description of the various embodiments of the present invention havebeen presented for purpose of illustration, but are not intended to beexhaustive or limited to the embodiments disclosed. Many modificationsand variations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the describedembodiments. The terminology used herein was chosen to best explain theprinciples of the embodiments, the practical application or technicalimprovement over technologies found in the marketplace, or to enableothers of ordinary skill in the art to understand the embodimentsdisclosed herein.

In addition, the term “or” is intended to mean an inclusive “or” ratherthan an exclusive “or.” That is, unless specified otherwise, or clearfrom context, “X employs A or B” is intended to mean any of the naturalinclusive permutations. That is, if X employs A; X employs B; or Xemploys both A and B, then “X employs A or B” is satisfied under any ofthe foregoing instances. Moreover, articles “a” and “an” as used in thesubject specification and annexed drawings should generally be construedto mean “one or more” unless specified otherwise or clear from contextto be directed to a singular form. As used herein, the terms “example”and/or “exemplary” are utilized to mean serving as an example, instance,or illustration. For the avoidance of doubt, the subject matterdisclosed herein is not limited by such examples. In addition, anyaspect or design described herein as an “example” and/or “exemplary” isnot necessarily to be construed as preferred or advantageous over otheraspects or designs, nor is it meant to preclude equivalent exemplarystructures and techniques known to those of ordinary skill in the art.

Further, what has been described above include mere examples of devicesand methods. It is, of course, not possible to describe everyconceivable combination of components or methods for purposes ofdescribing this disclosure, but one of ordinary skill in the art canrecognize that many further combinations and permutations of thisdisclosure are possible. Furthermore, to the extent that the terms“include,” “have,” “possess,” and the like are used in the detaileddescription, claims, appendices and drawings such terms are intended tobe inclusive in a manner similar to the term “comprising” as“comprising” is interpreted when employed as a transitional word in aclaim.

What is claimed is:
 1. A method, comprising: forming channel structureson a first surface of a silicon first wafer, wherein the channelstructures respectively comprise radial channels that extend fromcentral fluid distribution areas, and wherein integrated circuits areformed on a second surface of the silicon first wafer that opposes thefirst surface; and bonding a manifold wafer to the first surface of thesilicon wafer such that inlet openings formed through the manifold waferrespectively connect to the central fluid distribution areas, therebyenclosing the radial channels and forming a bonded structure.
 2. Themethod of claim 1, wherein the bonding the manifold wafer to the firstsurface of the silicon wafer comprises employing a thermally conductivebonding material.
 3. The method of claim 1, further comprising: removingportions of the manifold wafer respectively enclosing outward portionsof the radial channels, thereby forming outlet openings for the radialchannels.
 4. The method of claim 3, wherein the outlet openings areconfigured to direct liquid or vapor out of the radial channels in adirection about 90 degrees relative to the first surface of the siliconwafer.
 5. The method of claim 3, further comprising: dicing the bondedstructure between the channel structures, thereby forming a plurality ofchip structures, wherein one or more of the plurality of chip structurescomprise: a first channel structure of the channel structures; firstradial channels of the radial channels; a first inlet opening of theinlet openings; first outlet openings of the outlet openings; and atleast one first integrated circuit of the integrated circuits.
 6. Themethod of claim 5, further comprising: mounting a chip structure of theplurality of chip structures onto a substrate; attaching a cap to thechip structure and the substrate, thereby enclosing the chip structureon the substrate and forming outlet paths between the first outletopenings and the cap; forming an inlet path through the cap thatconnects to the first inlet opening; and forming one or more secondoutlet openings in the cap that connect to the outlet paths.
 7. Themethod of claim 6, wherein the inlet path is configured to receiveliquid coolant, wherein the first inlet opening is configured todistribute the liquid coolant to the first radial channels, wherein thefirst outlet openings are configured to expel vapor generated from theliquid coolant within the first radial channels into the outlet paths,and wherein one or more second outlet openings are configured to expelthe vapor from the outlet paths.
 8. The method of claim 1, furthercomprising: dicing the bonded structure between the channel structures,thereby forming a plurality of chip structures, wherein at least one ofthe plurality of chip structures comprises: a chip comprising, at leastone integrated circuit of the integrated circuits, a first channelstructure of the channel structures, wherein the first channel structurecomprises first radial channels of the radial channels and a firstcentral distribution area of the central distribution areas; and atleast a portion of the manifold wafer bonded to the chip and enclosingthe first radial channels, wherein the at least a portion of themanifold wafer comprises a first inlet opening of the inlet openingsthat connects to the first central fluid distribution area.
 9. Themethod of claim 8, further comprising: further dicing an outward portionof the part of the manifold wafer enclosing an outward portion of firstradial channels, thereby forming outlet openings for the first radialchannels.
 10. A method, comprising: forming channel structures on afirst surface of a manifold wafer, wherein the channel structuresrespectively comprise radial channels that extend from central fluiddistribution areas; and bonding the first surface of the manifold waferto a first surface of a silicon wafer, thereby enclosing the radialchannels and forming a bonded structure.
 11. The method of claim 10,wherein the silicon wafer comprises a plurality of integrated circuitsformed on or within the silicon wafer.
 12. The method of claim 10,further comprising: forming inlet openings through a second surface ofthe manifold wafer that respectively connect to the central fluiddistribution areas, wherein the second surface of the manifold waferopposes the first surface of the manifold wafer.
 13. The method of claim10, wherein the bonding the first surface of the manifold wafer to thefirst surface of the silicon wafer comprises employing a thermallyconductive bonding material.
 14. The method of claim 10, furthercomprising: removing portions of the manifold wafer respectivelyenclosing outward portions of the radial channels, thereby formingoutlet openings for the radial channels.
 15. The method of claim 14,wherein the outlet openings are configured to direct liquid or vapor outof the radial channels in a direction about 90 degrees relative to thefirst surface of the silicon wafer.
 16. The method of claim 14, whereinthe manifold wafer further comprises inlet openings through a secondsurface of the manifold wafer that respectively connect to the centralfluid distribution areas, wherein the second surface of the manifoldwafer opposes the first surface of the manifold wafer, the methodfurther comprising: dicing the bonded structure between the channelstructures, thereby forming a plurality of chip structures, wherein oneor more of the plurality of chip structures comprise: a first channelstructure of the channel structures; first radial channels of the radialchannels; a first inlet opening of the inlet openings; first outletopenings of the outlet openings; and at least one integrated circuit.17. The method of claim 16, further comprising: mounting a chipstructure of the plurality of chip structures onto a substrate;attaching a cap to the chip structure and the substrate, therebyenclosing the chip structure on the substrate and forming outlet pathsbetween the first outlet openings and the cap; forming an inlet paththrough the cap that connects to the first inlet opening; and formingone or more second outlet openings in the cap that connect to the outletpaths.
 18. The method of claim 17, wherein the inlet path is configuredto receive liquid coolant, wherein the first inlet opening is configuredto distribute the liquid coolant to the first radial channels, whereinthe first outlet openings are configured to expel vapor generated fromthe liquid coolant within the first radial channels into the outletpaths, and wherein one or more second outlet openings are configured toexpel the vapor from the outlet paths.